The Impact of Imaging Techniques Based on Vibrational Spectroscopy on the Molecular Characterization of Syndiotactic Polystyrene Co-Crystals

The application of imaging techniques based on vibrational spectroscopy to the characterization of different sPS systems is described. FTIR micro-spectroscopy was employed to investigate the photoisomerization patterns obtained by irradiation of a norbornadiene/sPS co-crystalline phase. As a further example, the analysis of a mixed polymorphic phase containing both the d and e helical modifications, is reported. FTIR imaging with polarized radiation allowed us to identify the two crystalline modifications and to determine their spatial distribution within the sample. Finally, the confocal-Raman characterization of a sulfonated sPS film is discussed. In this case, imaging and depth-profile measurements made it possible to quantify the sulfonation degree and the crystallinity along the thickness direction and to verify the distribution of reacted sites within the sample. The usefulness of imaging techniques based on vibrational spectroscopy for the molecular characterization of multicomponent systems based on sPS has been demonstrated.